TABLE 1. Summary of information contained in this NACI Statement.

1. WHAT	What is influenza? Influenza is a respiratory infection caused by influenza A and B viruses. In Canada it generally occurs each year in the late fall and winter months. Symptoms typically include the sudden onset of headache, chills, cough, fever, loss of appetite, muscle aches and fatigue, running nose, sneezing, watery eyes and throat irritation. Nausea, vomiting and diarrhea may also occur, especially in children. Most people will recover within a week or ten days, but some - including those 65 years of age and older and adults and children with chronic conditions - are at greater risk of more severe complications, such as pneumonia. Additional information about influenza is available on the Public Health Agency of Canada web site.
	What are influenza vaccines? There are currently eight seasonal trivalent influenza vaccines authorized for use in Canada. Each province or territory will advise which vaccines will be made available for the publicly-funded program in that jurisdiction. Seven of the seasonal influenza vaccines are trivalent inactivated vaccines (TIV), either split virus or subunit. Five of these (Agriflu®, Fluviral®, Fluzone®, Influvac®, and Vaxigrip®) are traditional intramuscular (IM) products that do not contain an adjuvant. The sixth (Fluad®) is an MF59-adjuvanted vaccine for persons ≥65 years of age that is also given IM. The seventh TIV product (Intanza®) is authorized for persons ≥18 years of age and is given by the intradermal route. Intanza is available in two formulations: 9 µg/strain for persons 18-59 years of age and 15 µg/strain for persons 60 years of age and older. The eighth product (FluMist®) is a live attenuated influenza vaccine (LAIV) that is authorized for use from 2-59 years of age. The virus strains in FluMist® are cold-adapted and temperature sensitive, so they replicate in the nasal mucosa rather than the lower respiratory tract, and they are attenuated so they do not produce classic influenza-like illness. Influenza vaccine is safe and well-tolerated and may be given to persons starting from six months of age (noting product-specific age indications and contraindications).
2. WHO	Who to immunize? Immunization programs should focus on: • those at high risk of influenza-related complications – adults and children with underlying health conditions, including morbid obesity; residents of nursing homes and other chronic care facilities; people ≥ 65 years of age; children 6 to 59 months of age; pregnant women; and Aboriginal peoples; • those capable of spreading influenza to individuals at high risk of complications – health care providers in facilities and community settings; household contacts of high-risk persons including infants <6 months of age; those providing care to children ≤ 59 months of age; and those providing services in closed settings to those at high risk (e.g. crew on a ship); and • those who provide essential community services. NACI also encourages influenza vaccine for all Canadians, because significant illness and societal costs also occur in people not considered to be at high risk of complications.
3. HOW	Dose, schedule, contraindications and precautions, and co-administration. Children who have been previously immunized with seasonal influenza vaccine and adults are to receive one dose of influenza vaccine each year. Children 6 months to <9 years of age receiving seasonal influenza vaccine for the first time should be given two doses, with a minimum interval of four weeks between doses. The route of administration and dosage varies by product (See section IV.3 of this statement for details). For intramuscular TIV, the dose is now 0.5 ml for all age groups. Persons who developed an anaphylactic reaction to a previous dose of influenza vaccine or to any of the vaccine components (with the exception of egg), or developed Guillain-Barré Syndrome (GBS) within six weeks of influenza vaccination should not receive a further dose. NACI now advises that most persons with egg allergy may be safely vaccinated with inactivated influenza vaccine (TIV) (See section IV.7 of this statement for details). Vaccination should be deferred in persons with serious acute febrile illness. There are additional contraindications for LAIV (See section IV.7 of this statement for details). Influenza vaccine, including LAIV, may be given at the same time as other inactivated or live vaccines. If LAIV (FluMist®) and other live vaccines (e.g. MMR) are not administered at the same visit, they should be separated by at least 4 weeks. Soreness at the injection site may occur after TIV and is more common with adjuvanted or intradermal vaccine. Fever and other systemic reactions are infrequent. The most common adverse events after LAIV are nasal congestion and runny nose. Influenza vaccine should be stored at 2-8°C and should never be frozen.
4. WHY	Counselling points for providers to emphasize with clients when discussing these recommendations. Vaccination is the most effective way to prevent influenza. Each year there is a new vaccine to protect against the influenza virus strains that are expected in the coming influenza season. Even if the strains have not changed, getting influenza vaccine every year is necessary to maximize protection. Annual influenza vaccination is encouraged for all Canadians, particularly those at high risk of influenza complications, those who could spread influenza to someone at risk and those who provide essential community services. Influenza vaccine is safe and well-tolerated.